Some work on this has been conducted during the 80ties and 90ties at ICARDA in Syria. Here are some references:

MCNEILL, A. M., HARRIS, H. C. & BECK, D. P. 1993. Fixation and cycling of nitrogen in a dryland legume-cereal production system. Farm Resource Management Program: Annual Report for 1992. Aleppo, Syria: ICARDA.

MCNEILL, A. M., PILBEAM, C. J., HARRIS, H. C. & SWIFT, R. S. 1998. Use of residual fertiliser 15N in soil for isotope dilution estimates of N2 fixation by grain legumes. Australian Journal of Agricultural Research, 49, 821-828.

MCNEILL, A. M., PILBEAM, C. J., HARRIS, H. C. & SWIFT, R. S. 1996. Seasonal variation in the suitability of different methods for estimating biological nitrogen fixation by grain legumes under rainfed conditions. Australian Journal of Agricultural Research, 47, 1061-1073.

JENKINSON, D. S., HARRIS, H. C., RYAN, J., MCNEILL, A. M., PILBEAM, C. J. & COLEMAN, K. 1999. Organic matter turnover in a calcareous clay soil from Syria under a two-course rotation. Soil Biology and Biochemistry, 31, 687-693.

EVANS, J., MCNEILL, A. M., UNKOVICH, M. J., FETTELL, N. A. & HEENAN, D. P. 2001. Net nitrogen balances for cool-season grain legume crops and contribution to wheat nitrogen uptake: a review. Australian Journal of Agricultural Research, 41, 347-359.

Regards, Carina

I think a recent paper attached here may be helpful for your question.

pls see this paper

Although several years have been passed since their publication, the list of papers provided by Carina Moeller (above) still very applicable to dry-land agriculture.  I am well aware of the work of McNeill et al. research team, one of the leading research team on dry-land agriculture .  I believe, they still have a very active research program, mainly focusing on legume based crop rotations in Southern and South-Western Australia and you may be able to find their recent publications easily.

-SJ

Dr.Phogat,if you see literature,many times the changes in available N estimated by alkaline permanganate method are  small and small changes brought by legume introduction  can not be detected in total N estimated(changes may not be statistically significant ) under under Indian conditions.